1. Field of the Invention
The present invention relates to a structure for mounting a terminal to a printed circuit board, and the structure is suitable for use in a transmitter-receiver unit for example.
2. Description of the Related Art
FIG. 3 is a sectional view showing a conventional terminal mounting structure for a printed circuit board and FIG. 4 is a partial perspective view thereof.
As shown in FIGS. 3 and 4, the conventional terminal mounting structure for a printed circuit board comprises a printed circuit board 1 formed with a predetermined electronic circuit and terminals 5 connected to the electronic circuit of the printed circuit board 1.
The printed circuit board 1 comprises a board 2 which is formed in the shape of a flat plate using a glass-filled epoxy resin for example, wiring patterns 3 formed in predetermined shapes by, for example, etching a copper foil on both the surface and the back of the board 2, and a plurality of electric components 4 such as an integrated circuit (LSI), a chip capacitor and a chip resistor, connected to the wiring patterns 3. Also near each of associated end faces 2a of the board 2 there are formed wiring patterns 3 on both the surface and the back of the board. A predetermined electronic circuit is formed by the electric components 4 and the wiring patterns 3.
Each terminal 5 is formed by punching and bending an electrically conductive metallic plate and it comprises a lead-out terminal portion 5a and a generally U-shaped holding portion 5b projecting in a direction perpendicular to the lead-out terminal portion 5a. The lead-out terminal portion 5a has a narrow part 5c and a wide part 5d. The holding portion 5b comprises two first retaining parts 5e bent nearly at right angles from the wide portion 5d and a second retaining portion 5f bent in L shape. Tip ends of the first and second retaining parts 5e, 5f are substantially in parallel with each other.
The terminal 5 comes into engagement with an end face 2a of the board 2 of the printed circuit board 1 so as to clamp the board 2. In this engaged state, the first retaining parts 5e of the holding portion 1 are abutted against a wiring pattern 3 formed on the back of the board 2, while the second retaining part 5f is abutted against a wiring pattern 3 formed on the board surface. Further, wiring patterns 3 on the surface and the back are connected together electrically through the terminal 5. The terminal 5 thus abutted against the wiring patterns 3 are fixed to the wiring patterns 3 by soldering (not shown).
A plurality of such terminals 5 are disposed at predetermined positions of the board 2.
Each terminal 5 is mounted to the printed circuit board in the following manner.
First, the electric components 4 are temporarily fixed to predetermined positions of the wiring patterns 3 formed on the board 2 and are then fixed to the wiring patterns 3 by soldering. Next, from an end face 2a of the board 2 and at a position where the generally U-shaped holding portion 5b of each terminal 5 will come into contact with predetermined wiring patterns 3 located near the end face 2a on the board 2, the holding portion 5b of the terminal 5 is brought into engagement with the wiring patterns 3 so as to clamp the board. Then, the wiring patterns 3 and the first and second retaining parts 5e, 5f of the holding portion 5b are fixed together by soldering. Now, the terminal mounting operation is completed.
In mounting each terminal 5 to the printed circuit board according to the conventional terminal mounting structure, however, when the generally U-shaped holding portion 5b of each terminal 5 is to be clamped onto the board 2 from an end face 2a of the board, any member (or position) serving as a reference in the terminal mounting operation is found neither on the board 2 side nor on the terminal 5 side, but the same operation is performed visually, so it is difficult to effect positioning of the terminal 5 relative to the board 2, thus giving rise to the problem that the terminal mounting operation is troublesome and difficult.
The terminal 5 thus mounted to the board 2 is then fixed to wiring patterns 3 by soldering. Before the soldering. However, the terminal 5 is attached merely by clamping generally U-shaped holding portion 5b onto the board 2, so if in this state anything should strike against the terminal 5, the terminal 5 will be dislocated easily, making soldering difficult.